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Title:
CONCRETE PAVEMENT LAYER WITH WASTE TIRE CHIP LAYER.
Document Type and Number:
WIPO Patent Application WO/2003/016632
Kind Code:
A1
Abstract:
The present invention relates to a concrete pavement layer with a section consisting of a waste tire chip layer formed on a water permeable concrete course or a conventional concrete course to have a thickness of 10 to 20mm.The waste tire chip layer is formed using waste tire chips crushed to a desired size.The concrete pavement layer is a functional pavement layer which exhibits a impact absorbing effect and a noise absorption effect upon wlking or traveling of automobiles,and which can posses water permeablility so as to permit supplying moisture to street trees and preventing the overflowing of rivers , in the dry season and the rainy season respectively.Also, it can contribute to the recycling of resources and the protection of environment, since waste tires that are environmental wastes are used as materials for pavements of footpath or a road.

Inventors:
Lee, Yeong-ryeol (2nd Floor, Hojung-villart 679, Irwon-don, Gangnam-gu Seoul 135-230, KR)
Application Number:
PCT/KR2002/001406
Publication Date:
February 27, 2003
Filing Date:
July 26, 2002
Export Citation:
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Assignee:
Lee, Yeong-ryeol (2nd Floor, Hojung-villart 679, Irwon-don, Gangnam-gu Seoul 135-230, KR)
International Classes:
E01C7/32; E01C7/35; E01C11/22; (IPC1-7): E01C7/26
Foreign References:
KR20010234646U
JPH01207506A1989-08-21
KR970132371A
KR970007959A1997-02-21
Attorney, Agent or Firm:
Koh, Yong-hoe (Sanwoo Bldg. 4th Floor, 1543-11 Seocho-don, Seocho-gu Seoul 137-070, KR)
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Claims:
What is Claimed is:
1. Concrete pavement layer with waste tire chip layer, which comprises : a concrete pavement layer; and a waste tire chip layer formed on the concrete pavement layer to a thickness of 10 to 20 mm.
2. The concrete pavement layer of Claim 1, in which the concrete pavement layer is selected from the group consisting of a water permeable concrete course, an asphalt concrete course, a cement concrete course and a concrete footpath block.
3. The concrete pavement layer of Claim 1, in which the concrete pavement layer is a water permeable concrete layer formed by mixing 1560 to 1716 kg/m3 of aggregates having a size of less than 13 mm (grain size range at which 90 to 100% of the aggregates are passed through a 13 mm sieve, 70 to 100% are passed through a 100 mm sieve, 0 to 20% are passed through a 5 mm sieve, and 0 to 5% are passed through a 2.5 mm sieve), 300 to 380 kg/m3 of cement, 84 to 133 kg/m3 of water and 0.2 to 0.5 kg/m3 of admixture.
4. The concrete pavement layer of Claim 1, in which the waste tire chip layer includes waste tire chips having a single grain size of 1.2 to 13 mm, 10 to 25 g of binder relative to 100 g of the waste tire chips, and 1 to 5 g of pigment relative to 100 g of the waste tire chips, so that it has water permeability.
5. The concrete pavement layer of Claim 1, in which the waste tire chip layer includes waste tire chips having a size of less than 13 mm, 10 to 25 g of binder relative to 100 g of the waste tire chips, and 1 to 5 g of pigment relative to 100 g of the waste tire chips, so that it has water impermeability.
6. The concrete pavement layer of Claim 4, in which the waste tire chips have a grain size range selected from the group consisting of 1.22. 5 mm, 1.25 mm, 1.27 mm, 1.210 mm, 1.213 mm, 2.55 mm, 2.57 mm, 2.510 mm, 2.513 mm, 57 mm, 510 mm, 513 mm, 710 mm and 713 mm.
7. The concrete pavement layer of Claim 5, in which the waste tire chips have a grain size range selected from the group consisting of 2.5 mm, 5 mm, 7 mm, 10 mm and 13 mm.
8. The concrete pavement layer of Claim 4 or 5, in which the binder is selected from the group consisting of urethane, epoxy, acryl, sulfide, ester, phenol, olefin, imide, rubber, acrylateand polyenebased binder.
Description:
CONCRETE PAVEMENT LAYER WITH WASTE TIRE CHIP LAYER Technical Field The present invention relates in general to a concrete pavement layer with a section consisting of a waste tire chip layer formed on a concrete or permeable concrete course, such as a concrete pavement, an asphalt concrete pavement or a concrete block, in which the waste tire chip layer is formed to have a thickness of 10 to 20 mm using waste tire chips crushed to a desired size. More particularly, the present invention relates to a concrete pavement layer with a waste tire chip layer formed on a conventional water permeable concrete base course or a concrete pavement layer having water permeable concrete blocks, on which a waste tire chip layer, a mix course containing recycled chips obtained by crushing a waste tire formed, whereby the concrete pavement layer has excellent durability and stiffness, secured resilience, noise absorption and water permeability, and does not stay water on its surface with increased skid resistance, so that it is effective in paving a footpath, a bicycle road, a promenade of parks and golf clubs, and the like.

Background Art A conventional block for paving a footpath includes a general footpath block which is produced by mixing aggregates (such as crushed stones), sands and cements at a desired ratio, forming the mixture into a desired shape using a mold, and then curing it. This footpath block is non-permeable such that rainwater is led onto the footpath block, flows into rivers and contributes to river overflowing.

Also, in the case of this block, rainwater does not permeate into the ground below the footpath blocks, so that environmental problems can occur in that an

underground ecosystem is broken and soil is made desert due to insufficient underground water. To overcome these problems, a water permeable footpath block is thus used. However, it is difficult for this conventional water permeable footpath block to be used, since voids of the footpath block are clogged when forming cuttings. Moreover, it has problems in terms of economical efficiency and usefulness, since it has no resilience so that it gives a stiff feel on walking.

Fig. 1 at its left side shows a conventional water permeable concrete pavement layer 100 consisting of a base road 110, a filter course 120, a crushed stone base course 130 and a water permeable concrete course 140, sequentially from a lower part. The water permeable concrete course 140 allows rainwater to permeate into the crushed stone base course 130, the filter course 120 and the base road 110 through voids formed between aggregates of the water permeable concrete course, as indicated as the downward arrow, and causes the natural evaporation of moisture, as the upward arrow. Thus, it is advantageous in that it helps the growth of plants such as street trees, and allows rainwater to penetrate into the ground in the rainy season including conditions of a heavy rain and a pouring rain so as to be stored in soil so that the overflowing of rivers is prevented.

Also, it advantageously prevents rainwater from staying or flowing on a road so as to make a walker easy to move. Because of such advantages, a road or footpath having the permeable concrete course formed at its surface course is increasingly popularized as an alternative method to a conventional pavement method in which rainwater is led to a drainage port 160 from a conventional asphalt concrete course 150, and finally transmitted to rivers, a sewage treatment plant or the public waters, as shown at the right side of Fig. 1.

In paving the road, the footpath or the bicycle road to have water permeability, there are used water permeable asphalt concrete and permeable cement concrete. However, in the case of the permeable asphalt concrete, there are functional problems in that it results in the serious deformation of the road surface in the summer season and also clogging of the voids of the road surface due to the viscosity of asphalt.

On the other hand, the permeable cement concrete employs little or no fine aggregates and controls a slump value to nearly zero so as to secure continuous voids, so that permeation is achieved. However, this permeable cement concrete has the following problems. Namely, in order to make a surface beautiful, the surface is applied with an epoxy-based paint, but in the case of a slant road, it causes a skid problem as compared to a general cement concrete. Also, since it is a rigid pavement, it hurts a person when the person is fallen down on its surface.

Moreover, it has a rough surface and a poor strength, so that the surface-peeling phenomenon can occur. Also, its void can be covered with dust so that water permeability is rapidly reduced. To remove the covered dust, a maintenance and management cost for the road is excessively consumed.

Furthermore, due to a recent development in automobile industry, the generation amount of waste tires was rapidly increased and it has become a social problem. For this reason, the disposal of the waste tires must be solved immediately, but is under difficult conditions due to an insufficient landfill, environmental pollution, and avoidance of dislike establishment by residents, etc.

Thus, the disposal of the waste tires becomes a problem to be solved immediately in terms of the efficient recycling of resources and the protection of environment.

Also, the waste tires are based on various synthetic rubbers and they are wastes

having high heat capacity. However, they cannot be incinerated at random due to a problem of the environmental pollution (generation of dioxin) and also are increased with respect to their accumulated amount due to low economical efficiency in an existing disposal process. Thus, they have problems in that they can occur the environmental disruption and various environmental problems. For these reasons, the appropriate use of the waste tires is more urgently required also due to an interest in recycling according to the improvement of living conditions.

For this, rubber blocks were developed, which are produced by adding adhesive and pigment to fine rubber chips obtained by crushing and grounding of the waste tires or rubbers, and introducing the resulting mixture into a specific mold and then forming it into a desired shape. Among the rubber blocks, a rubber block made of pure rubber, when being exposed to solar heat, shows an increased temperature at its surface and thus significantly smells of rubber. Also, in the case of a conventional block having a two-layer construction, it disadvantageously absorbs high solar heat in the summer season, so that the temperature of its surface is rapidly increased and its resilient layer is separated from a lower support layer.

Furthermore, in some rubber blocks, several holes are artificially formed in the blocks to render the blocks permeable, but do not exhibit a great effect.

Therefore, there is an urgent demand for the development of a pavement layer construction method, which permits efficient disposal of the waste tires, and at the same time, permits solving the above problems with the construction of the conventional pavement layer, such as the footpath block for pavement or the water permeable concrete.

Disclosure Of Invention Accordingly, the present invention has been made to solve the above- mentioned problems occurring in the pavement layer construction method and the disposal of the waste tires, according to the prior art, and an object of the present invention is to provide a concrete pavement layer having a waste tire chip layer, which permits efficiently disposing the waste tires whose generation amount is rapidly increased due to the development of the automobile industry and whose disposal are under difficult conditions due to an insufficient landfill, environmental pollution caused by treatment facilities thereof (generation of dioxin on incineration), and avoidance of dislike establishment by residents.

Another object of the present invention is to provide a concrete pavement layer having a waste tire chip layer, in which the concrete pavement layer permits smoothly supplying life-giving water to street trees by the bi-directional permeability by which rainwater permeated into the ground is evaporated to the earth's surface in the dry season, and in which the concrete pavement layer can prevent the river overflowing which can occur by the outflow of rainwater itself into public waters or city rivers, and in which the concrete pavement layer permits rapidly permeating rainwater into a road or a footpath so that it allows safe and comfortable passage of an walker on the road by the high skid resistance of the road and can remove the visual hindrance caused by diffused reflection of rainwater stayed on the road or footpath, and in which the concrete pavement layer permits reduction of automobile noise due to a good noise absorption property.

Another object of the present invention is to provide a concrete pavement layer having a waste tire chip layer which can provide a colored water permeable

concrete which can circulate air and permeate water by voids formed in the internal structure of a block having waste tire chips.

Another object of the present invention is a concrete pavement layer having a waste tire chip layer, which permits reducing fatigue of a wallcer on walking by virtue of resilience of a waste tire, minimizing a wound of the walker even on falling down of the walker, and protecting the joint of the walker, including old and feeble persons.

Brief Description Of The Drawings Further objects and advantages of the invention can be more fully understood from the following detailed description taken in conjunction with the accompanying drawings, in which: Fig. 1 is cross-sectional views showing a conventional water permeable concrete pavement layer and an asphalt concrete pavement layer, respectively.

Fig. 2 is a cross-sectional view showing a concrete pavement layer having a waste tire chip layer formed therein, according to embodiment 1 of the present invention.

Fig. 3 is a flow chart for forming the concrete pavement layer according to embodiment 1.

Figs. 4 and 5 show alternatives to embodiment 1 of the present invention.

Fig. 6 is a cross-sectional view showing a water permeable concrete pavement layer having a waste tire chip layer formed therein, according to embodiment 2 of the present invention.

Figs. 7 and 8 are a perspective view and a cross-sectional view (A-A) showing the water permeable concrete pavement layer according to embodiment 2

of the present invention, respectively.

Best Mode For Carrying Out The Invention To achieve the objects of the present invention as described above, as shown in Fig. 2, a waste tire chip layer 200 is formed on a water permeable concrete course 340 of a concrete pavement layer 300 formed on a road 310. The concrete pavement layer 300 consists of a filter course 320, a crushed stone base course 330 and a water permeable concrete course 340. Alternatively, as shown in Fig. 6, the waste tire chip layer 200 is formed on a water permeable concrete course 510 constituting the lower part of a water permeable concrete block 500 formed on a filter course 420 which constitutes a water permeable concrete block pavement layer 400 formed on a road 410. Hereinafter, embodiment 1 and 2 of the present invention will be described in which the waste tire chip layer 200 is formed on the concrete pavement layer 300 and the water permeable concrete block pavement layer 400, respectively.

Embodiment 1 (where a waste tire chip layer is not formed on a concrete pavement layer) Fig. 2 shows a concrete pavement layer 300 with a waste tire chip layer formed thereon as embodiment 1. As shown in Fig. 2, on the lower layer of the pavement layer including a filter course 320 and a crushed stone base course 330, a water permeable concrete base course 340 is formed with aggregates of less than 13 mm, compacted, and then cured. After cutting process on the water permeable concrete base course 340, a waste tire chip layer 200 is formed on the water permeable concrete course 340 to a thickness of 10 to 20 mm, compacted and then

cured. At this time, the waste tire chip layer 200 contains binder, pigment, and waste tire chips whose grain size range is controlled to 1.2-2. 5 mm, 1.2-5 mm, 1.2- 7 mm, 1.2-10 mm, 1.2-13 mm, 2.5-5 mm, 2.5-7 mm, 2.5-10 mm, 2.5-13 mm, 5-7 mm, 5-13 mm, 7-10 mm and 7-13 mm depending on their applications.

Alternatively, as shown in Figs. 4 and 5, the waste tire chip layer 200 is covered additionally on a water permeable concrete pavement, a concrete pavement, an asphalt concrete pavement or a footpath block that is a conventional built-in pavement. Then, it is compacted and cured.

The water permeable concrete base course 340 is one in which concrete is rendered water-permeable by controlling the grain size of the aggregates. As the concrete base course, the color water permeable concrete as described in Korean Patent No. 132371 owned by the applicant can be used.

Namely, there can be used a water permeable concrete in which aggregates having their grain size of 6-10 mm are used without fine aggregates so as to improve water permeability. However, since this water permeable concrete course is finished at an upper surface by itself, coarse aggregates can provide a rough surface. Thus, the grain size is limited within less than 10 mm in the case of aggregates. However, in the present invention, since the waste tire chip layer 200 is additionally formed on the water permeable concrete course 340, the aggregates used in the water permeable concrete course may be somewhat coarse as compared to those of the Korean Patent No. 132371 as described above.

As a result, a size of the aggregates used in the water permeable concrete course of the present invention is preferably in the range of 5 to 13 mm, but not limited thereto. A water permeable concrete layer may contains aggregates with their grain size of less than 5 mm or more than 13 mm.

As a mix proportion used in the water permeable concrete base course, there may be used a mix proportion consisting of 1560 to 1716 kg/m3 of aggregates having their grain size from 5 to 13 mm (grain size range at which 90-100% of the aggregate are passed through a 13 mm sieve, 70-100% are passed through a 100 mm sieve, 0-20% are passed through a 5 mm sieve, and 0-5% are passed through a 2.5 mm sieve), 300 to 380 kg/m3 of cement, 84 to 133 kg/m3 of water (water: cement ratio of about 25 to 35%), and 0.2 to 0.5 kg/rn of admixture. Other mix proportions may be used.

The waste tire chip layer 200 used in the present invention contains waste tire chips having a grain size range selected from 1.2-2. 5 mm, 1. 2-5. mm, 1.2-7 mm, 1.2-10 mm, 1.2-13 mm, 2.5-5 mm, 2.5-7 mm, 2.5-10 mm, 2.5-13 mm, 5-7 mm, 5-10 mm, 5-13 mm, 7-10 mm or 7-13 mm with respect to applications.

Also, the waste tire chip layer contains 10 to 25 g of binder and 1-5 g of inorganic pigment relative to 100 g of the waste tire chips. Namely, since the waste tire chip layer is formed while a grain size range of the waste tire chips varies within the fourteen size ranges and its water permeability will be improved in the order of the greater size range of the waste tire chips, the size range of the waste tire chips may be suitably selected, according to the object of their usages, including a footpath and a road, in which the waste tire chip layer is formed.

As the binder, there may be used a variety of resins that are based on urethane, epoxy, acryl, sulfide, ester, phenol, olefin, imide, rubber, and acrylate.

Such binders serve to bind the waste tire chips together and are used at a varied amount depending on the kind of the binder.

The inorganic pigment serves to render the waste tire chip layer colored, and does not need to be mixed into the waste tire chip layer, and can be treated in a

separated process. Namely, after the surface of the formed waste tire chip layer is applied with polymers including epoxy, urethane and acryl, the surface is applied with the pigment and colored. In this way, it is possible to make the waste tire chip layer colored.

Table 1 below shows examples of mix proportions for a waste tire chip layer according to various sizes of the waste tire chips. Examples of mix proportions according to sizes of 2.5-13 mm, 5-7 mm, 5-10 mm, 5-13 mm, 7-10 mm and 7-13 mm did not exhibit a significant difference from the mixes of Table 1 and thus were omitted.

Table 1: Example No. Waste tire Binder (g) Pigment (g) Size of waste tire chips (g) chips 1100"2141. 2-2.5 mm 2 100 21 4 1. 2-5 mm 3 100 20 4 1. 2-7 mm 4 100 20 4 1. 2-10 mm 5 100 20 4 2. 5-5 mm 6 100 20 4 2. 5-7 mm 100 20 2. 5-10 mm

As the waste tire chips in Table 1, a product produced and sold by KORECO (Korea Resources Recovery & Reutilization Corporation), Korea, was purchased and used. The waste tire chips sold by KORECO have sizes of 5 mm, 7 mm and 10 mm. The purchased waste tire chips of the respective size were sieved using a 2.5 mm sieve and a 5 mm sieve to control their sizes, and the waste tire chips remaining on the sieves were used. Although chips having the sizes of 2.5 mm and 13 mm are not currently sold, it can be possible that the chips of such sizes are used.

As the binder in Table 1, urethane-based binders were used, which are commercially available under the trademarlc of PR-2000-85 from Aekyung Chemical co. , Ltd, Korea, and the trademark of nanothane 69 from Byucksan Chemical Corporation, Korea.

Then, the waste tire chips were subjected to water permeability test according to their size.

The water permeability of the waste tire chip layer varies depending on the size of the chips constituting the chip layer. To evaluate the water permeability that varies depending on the size of the waste tire chips, permeability coefficient was measured and indicated in Table 2 below. (Examples of mixes according to sizes of 2.5-13 mm, 5-7 mm, 5-10 mm, 5-13 mm, 7-10 mm and 7-13 mm did not exhibit a significant difference from the mixes of Table 2 and thus were omitted.) Table 2 : Example No. Size of waste tire chips Permeability coefficient 1 1. 2-2.5 mm 2. 74 x 10-2 2 1. 2-5 mm 2. 94 x 10-2 3 1. 2-7 mm 3. 12 x 10-2 4 1. 2-10 mm 3. 38 x 10-2 5 2. 5-5 mm 3. 17 x 10-2 6 2. 5-7 mm-3. 42 x 10-2 7 2. 5-10 mm 3. 91 x 10-

The permeability coefficients in Table 2 were calculated according to the following equation: K = L x a/A (tl.-t2) x ln (hl/h2), where K is a permeability coefficient (cm/sec), L is the thickness of a surface course of a pavement layer (cm), a is the cross-sectional area of a container (cm2), A is the cross-sectional area of water permeation (cm²) h1 is a water level (cm) upon starting of the measurement, h2 is a

water level (cm) upon termination of the measurement, and tl-t2 is a water permeation time.

The calculated permeability coefficients do not show a great difference because compaction is low and voids between the waste tire chips are large.

Thus, where the waste tire chip layer is applied on the water permeable concrete pavement layer, it will be formed with the application of pressure, and thus is expected to have a somewhat lower permeability coefficient. Where the chip layer is applied on the concrete pavement layer and the binder is used at an increased amount, the voids are clogged so that the waste tire chip layer may also have a somewhat lower permeability coefficient.

The above results were measured in a state where the chip size was controlled such that the waste tire chip layer had the water permeability. If water impermeability is required in the waste tire chip layer, the waste tire chips of the sizes of 5 mm, 7 mm and 10 mm sold by KORECO may be mixed as they are. The above sold chips contain grains of various sizes ranging from a fine size to a given size. Thus, if the purchased chips are used intact, they have the water impermeability so that the waste tire chip layer may have the water impermeability.

Hereinafter, processes for forming a color concrete layer having the waste tire chip layer of the present invention will be described with Fig. 3.

Process 1 A road 310 is regulated and then compacted so as to exhibit a sufficient bearing capacity. On the compacted road, a filter course 320 made of sand and the like as a subbase course is formed so as to prevent subgrade soil from being infiltrated into a roadbed.

Process 2 On the filter course 320, a crushed stone base course 320 as a subbase course is formed and compacted into a desired shape with men or using a dozer in order that materials are not separated. At this time, the compaction is conducted using a roller or a compactor at the optimal moisture content. As the materials for the crushed stone base course 330, randomly crushed clear stones of less than 25 mm, crushed stones of a controlled size, recycled concrete aggregates and the like can be used.

Process 3 The water permeable concrete base course 340 is formed on the crushed stone base course 330 and compacted. Aggregates having a size of 5 to 13 mm are used for the water permeable concrete base course 340. The base course 340 is preferably wet cured so as to secure a desired strength (compression strength of more than 100 kg/cm2) and permeability (permeability coefficient of more than 1 x 103 cm/sec).

Process 4 Once the water permeable concrete base course is cured, cuttings are formed. To prevent cracking, the water permeable concrete base course is subjected to cutting and water cleaning. Since it is covered with the waste tire chip layer 200 at its upper surface, it is not subjected to sealing.

Process 5 A waste tire chip mix of waste tire chips, binders (based on urethane, epoxy or acryl) and pigments is applied on the water permeable concrete base course to a thickness of 10 to 20 mm, and compacted using a hand roller or a compactor. At this time, the roller or compactor is applied with oil or chemicals such that the

waste tire chips are not adhered thereto. Also, passage is prohibited until it is cured.

At this process, in order to make strong adhesion between the courses, a primer is applied before forming the waste tire chip layer. At this time, the waste tire chip layer is formed to a thickness of 10 to 20 mm in such a manner that its flatness can be maintained. Then, it is compacted to have a permeability coefficient of more than 1 x 10-3 cm/sec. Where it is compacted in this way, a part of the waste tire chip layer fills voids and cuttings of the water permeable concrete base course 340, achieving more perfect adhesion between the two courses.

The waste tire chips are used at various grain size range selected from 1.2- 2.5 mm, 1.2-5 mm, 1.2-7 mm, 1.2-10 mm, 1.2-13 mm, 2.5-5 mm, 2.5-7 mm, 2.5- 10 mm, 2.5-13 mm, 5-7 mm, 5-10 mm, 5-13 mm, 7-10 mm and 7-13 mm and so on with respect to their permeability. Where the waste tire chip layer is formed to have the water impermeability, the waste tire chips having their largest size of 2.5 mm, 5 mm, 7 mm, 10 mm or 13 mm are used. If the coloring pigment is added at this process, it is preferable to use the pigment at the amount of less than 5% by weight relative to the weight of the waste tires.

Process 6 If the pigment is not used in the waste tire chip layer 200, the surface of the chip layer can be applied with polymers including epoxy, urethane or acryl, so as to be colored. In this case, there is an effect of increasing the surface strength of the chip course in addition to coloring the chip layer.

According to the above processes, it is possible to form a new pavement layer having the waste tire chip layer on a given footpath or road. However, as shown in Fig. 4, the waste tire chip layer may be additionally formed on a base water permeable course 610 formed previously on the road that is divided by a

boundary line between a footpath and a roadway. Furthermore, as shown in Fig. 5, the waste tire chip layer 200 may be additionally formed on a concrete, asphalt concrete or concrete footpath block 620 formed previously.

Embodiment 2 (where a waste tire chip layer is formed on a water permeable concrete block pavement layer) Fig. 6 shows embodiment 2 of the present invention where a concrete pavement layer having a waste tire chip layer is formed on a water permeable concrete block pavement course 400. As shown in Fig. 6, on a water permeable concrete course 510 formed of aggregates of 5-13 mm and constituting the lower part of a water permeable concrete block 500, a waste tire chip layer 200 is formed to a thickness of 10-20 mm. The waste tire chip layer 200 contains waste tire chips whose size range is controlled to 1.2-2. 5 mm, 1.2-5 mm, 1.2-7 mm, 1.2-10 mm, 1.2-13 mm, 2.5-5 mm, 2.5-7 mm, 2.5-10 mm, 2.5-13 mm, 5-7 mm, 5-10 mm, 5-13 mm, 7-10 mm or 7-13 mm depending on their applications. Also, the chip layer 200 contains binders and pigments.

The water permeable concrete block 500 formed of the water permeable concrete course 510 is one in which the lower part of the water permeable concrete block is rendered permeable by controlling the size of aggregates in the same manner shown as embodiment 1. For this concrete block, the color water permeable concrete as described in Korean Patent No. 132371 may be used. A mix used in the water permeable concrete block 500 formed of the water permeable concrete course 510 can be produced by mixing 1560 to 1716 kg/m3 of aggregates having a size of less than 13 mm (grain size range at which 90-100% of aggregates are passed through a 13 mm sieve, 70-100% are passed through a 100 mm sieve, 0-

20% are passed through a 5 mm sieve, and 0-5% are passed through a 2.5 mm sieve), 300 to 380 kg/m3 of cement, 84 to 133 kg/m3 of water (water: cement ratio of about 25 to 35%), and 0.2 to 0.5 kg/m3 of admixtures.

The mix produced as described above exhibits a permeability coefficient of 1 x 10-3 cm/sec, and a compression strength of 100 to 300 kg/cm2.

The waste tire chip layer 200 is the same as that of embodiment 1.

Fig. 6 is a cross-sectional view showing the concrete pavement layer having the waste tire chip layer formed thereon, according to embodiment 2. Figs. 7 and 8 are a perspective view and a cross-sectional view of the water permeable concrete block used in embodiment 2, respectively.

Namely, as shown in Fig. 6, the water permeable concrete block 500 having the waste tire chip layer 200 formed thereon is formed on a water permeable concrete block pavement layer 400 consisting of a road 410 and a filter course 420 such that the waste tire chip layer 200 forms the upper part of the concrete block 500 while the water permeable concrete course 510 forms the lower part of the block 500.

In this case, the waste tire chip layer is formed such that it is greater in height than that of the water permeable concrete layer, the lower part of the block by about 1 to 2 mm. The conventional water permeable block has a problem associated with the treatment of joints, but in embodiment 2 of the present invention, the waste tire chip layer can be formed as it is, using the resilience of the waste tire chips, without filling the joints with sand.

The water permeable concrete block 500 having the waste tire chip formed thereon is formed according to the following procedure:

In order to form the lower part of the block formed of the water permeable concrete course 510, water permeable concrete is poured and formed into a desired shape in a mold, subjected to heating/pressurization, and then firstly cured. Once the water permeable concrete course 510 is cured, the waste tire chip mix is introduced on the course 510 and cured to form the waste tire chip layer 200.

In forming the waste tire chip layer 200 into a desired shape, if the chip layer 200 is applied with high pressure, voids of the chip layer 200 are clogged so that the chip layer does not exhibit the water permeability. Thus, it is preferred that the chip layer 200 is pressurized to suitable pressure without applying additional heat. Once it is cured to some degree, it is removed from the mold and subjected to natural curing, thereby forming the water permeable concrete block having the waste tire chip layer formed thereon. The formed block is disposed on the pavement course 400 consisting of the road 400 and the filter course 420, thereby forming the water permeable concrete block pavement layer.

Fig. 7 is a perspective view showing the formed water permeable concrete block 500 having the waste tire chip layer formed thereon, and Fig. 8 is the cross- sectional view taken along the line A-A of Fig. 7, which shows the water permeable block 500 having the waste tire chip layer formed thereon. From Figs. 7 and 8, it can be found that the waste tire chip layer 200 is formed on the water permeable concrete course 510 having a desired cross-sectional area so as to form the water permeable concrete block 500 of a double layer structure.

Industrial Applicability The footpath and road having the concrete pavement and water permeable concrete block formed of the concrete pavement layer having the waste tire chip

layer thereon according to the present invention can provide life-giving water to street trees, since rainwater permeated into the ground can be evaporated as moisture in the dry season. Also, they contribute to the prevention of the overflowing of public waters, drainage systems and rivers, under the condition of a heavy rain or a pouring rain and in the rainy season. Also, they allow for the safe passage of a walker on the road, since water is not fully stayed and also not flows on the road. Also, they permit the safe movement of automobiles, since the road has the increased skid resistance. Moreover, they can significantly reduce the diffused reflection caused by moisture stayed on the road, and thereby remove the visual hindrance phenomenon. Furthermore, they facilitate the reduction of automobile noise due to their good noise absorption properties. In addition, they permit recycling of the waste tires occurring the environmental problem, so that they exhibit a great effect in terms of the protection of environment. Finally, they permit reducing fatigue of a walker by absorbing impact by virtue of resilience of rubber on walking, and can reduce a wound of the walker even when the walker is fallen down on the road.

Although preferred embodiments of the present invention have been described for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.




 
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